The present invention relates to a color imaging device, and more particularly to the suppression of false color signals in a color imaging device of the spatial multiplexing type.
The color imaging device of the spatial multiplexing type wherein a mosaic color filter formed of a plurality of filter elements adapted to transmit light of wavelength regions different from one another are arrayed regularly in the row and column directions and the color filter is arranged in front of the image pickup face of a photoelectric device so as to make it possible to derive two or more different color signals from the single photoelectric device, is suited for an imaging device which can be made small in size and light in weight. Recently, a very small-sized color camera has been realized by employing as the photoelectric device a solid-state imaging device produced by the semiconductor integrated circuit technology and combining it with the spatially-multiplexing color filter.
In the color camera of the spatial multiplexing type, image signals of two or more color components are provided from the photoelectric conversion portion in a predetermined sequence, and are processed by a signal processing circuit designed in accordance with a filter structure so as to be converted into the color signals and a luminance signal. As one aspect of such signal processing, there has been known the form in which at least some of the filter elements constituting the mosaic color filter are made complementary light transmitting filter elements or panchromatic light transmitting filter elements, and the image signals of picture elements corresponding to these filter elements and those of picture elements proximate to the first-mentioned picture elements in the row direction or column direction are added and subtracted, whereby the predetermined color signals are demodulated. According to this form, the utilization factor of light incident on the photoelectric device is higher than in a case where the image signals of respective picture elements are separated by the use of a filter consisting only of primary color lighttransmitting filter elements, so that the sensitivity of the camera can be enhanced advantageously. In addition, it becomes possible to obtain stable luminance signals of little moire in accordance with the arrayal of the filter elements.
However, the above spatial multiplexing method employing the filter elements of the complementary colors premises that the images of the two picture elements to be used for the demodulation operation of the color signal are correlative to each other. Accordingly, it has the disadvantage that a false color signal not existent in an object to-be-imaged is demodulated in a place lacking the correlation, i.e., in a picture element located at the boundary between two patterns in the object to-be-imaged.